I love TB and have been using it for many years (and also Firefox)... Anytime a new versión of TB comes out I try it, but I find always the same bug (maybe it has others but I didn't noticed!). I have installed the recent 52.6.0 and the first I test is this: to answer an email. When the answer window pops up, there is no address!!! (I should put it manually!). Luckily I always have the 45.8.0 installer at hand and once more I downgrade TB. I wonder why the TB guys don't fix that once for all. Or maybe I haven't find the right hidden option for geting that. Please tell if I'm wrong with this or I'm the only one having this bug. Thanks.

Please tell if I'm wrong with this or I'm the only one having this bug.

OK, you're wrong. We're not seeing reports of that in any numbers so it's not necessarily a bug in the program but could be a conflict with extensions or settings.Does the same thing occur if you launch the application in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode

So, that's the problem! Contact Photo! Well, that seems a(nother) good reason to me for holding in v 45.8. Also because of Contact Side bar which became incompatible with the newest versions! Thanks a lot for the tips and for clearing things up.

Also because of Contact Side bar which became incompatible with the newest versions! Thanks a lot for the tips and for clearing things up.

No need for an extension to display contacts in a side bar in Thunderbird's more recent version. Just press F9 when in the composition window, or use menu path View->Contact Sidebar in that same window.